<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.bootcss.com/vue/2.6.10/vue.js"></script>
</head>
<body>
    <div id="app">
        <h4 v-for="(item,index) of arr">
            {{index}} {{item}}
        </h4>
    </div>
    <script>
        new Vue({
            el: "#app",
            data: {
                arr:["html","css","js"]
            }
        })
    </script>
</body>
</html>